Feeding affects reproductive performance and reproductive endocrinology in the gilt and sow

Abstract

The pig is considered to be a highly prolific species with ahigh ovulation rate and if mated at the right moment, thesow also holds a very high probability of pregnancy. It isgenerally accepted that little variation in live weight of thesow throughout the production cycle is associated withhigh fertility and improved longevity. This goal requireshigh energy intake during lactation, which may beachieved by ad libitum feeding with high energy high pro-tein lactation diet without feed restriction, especially dur-ing the last part of lactation. In endocrinological terms,gonadotrophin secretion is affected by suckling and met-abolic messengers, which transfer information regardinglactation and metabolic state of the dam. These messagesare received by the hypothalamo-pituitary axis and even-tually follicular development is either inhibited orencouraged, depending on the messages. Managementpractices such as intermittent suckling are developed toalleviate the sow to meet with the metabolic challengesimposed by lactation and expected fertility. After mating,social stress and restricted feeding may create a situationwhere embryonic survival and pregnancy is jeopardized.The risk of losing embryos/pregnancy may be highestwhen individual sows experience considerable food dep-rivation for longer than two days around implantation.Feeding a sow group more may provide the farmer withsimple solution to problems with early pregnancy.Approaching term, compromising between high birthweigh of newborn piglets associated with abundant feed-ing and a feed restriction together with increase in fiber toimprove intestinal function may be the strategy of choice.